Small bone fractures that develop in response to repetitive, cumulative trauma are known as stress fractures. These are fractures where bones are injured by overuse, they are commonly found in the spine, vertebrae, leg bones, feet, and the pelvis. They result from the accumulated trauma from repeated submaximal loading, such as running or jumping
The correct answer is small hydrophobic molecules.
The smaller the molecule and the more hydrophobic, or nonpolar, it is, the more rapidly it will diffuse across a membrane. It is because of the composition of membrane (lipid bilayer). By contrast, membrane is highly impermeable to charged molecules (ions), no matter how small they are.
Anaphase I begins when the two chromosomes of each bivalent (tetrad) separate and start moving toward opposite poles of the cell as a result of the action of the spindle. Notice that in anaphase I the sister chromatids remain attached at their centromeres and move together toward the poles.
